| 摘要 |
PURPOSE:To enhance the combustibility of an engine upon cold condition of the engine, by adjusting the opening and closing of a timing valve in a Miller cycle engine upon cold condition of the engine so that the engine is operated as an Otto cycle engine. CONSTITUTION:Each engine cylinder incorporates with two intake valves 12a, 12b, and the intake valve 12a is provided with a rotary type timing valve 24 which opens upon termination of suction stroke to perform adiabatic expansion so that the engine operates as a Miller cycle engine. The opening and closing timing of the timing valve 24 is adjusted by a control device 71 through a shaft phase adjusting means 26 composed of inclined teeth between the shaft 39 of a valve drive pulley 27 and rotary shaft 38 of the valve. When the cold condition of the engine is detected, the control device 71 sets the opening and closing timing of the timing valve to be made to be substantially equal to that of the intake valve 12a so that it apparently establish a condition in which no timing valve is provided, and therefore, the engine is operated as an Otto cycle engine to eliminate the adabatic expanstion in the timing valve. |
